The present invention relates to an ink jet print head and a method of manufacturing the same, and more particularly to an ink jet print head which uses piezoelectric elements as drive sources for drop generators for generating and discharging ink drops and a method of manufacturing the same.
There is known an ink jet print head which uses elements made of lead zirconate titanate (PZT) piezoelectric material (referred to as PZT element) for the drive sources for ink drop ejecting generators for generating ink drops or droplets, i.e., the elements for transducing electric energy into mechanical energy. The ink jet print head is generally formed with a head base, a vibrating plate, and PZT elements. A number of ink passages (ink cavities and the like) are formed in the head base. The vibrating plate is formed over the head base while covering all the ink passages formed therein. The PZT elements are formed on the regions on the vibrating plate, which correspond in position to the ink cavities. In operation, electric fields are selectively applied to the PZT elements, to thereby cause flexural displacements in these elements. With the displacements, inks contained in the ink passages associated with the PZT elements placed under the applied electric fields are forcibly shot forth in the form of ink drops or droplets, through the related ink discharge orifices formed in the nozzle plate.
In a case where the head base is formed of a single-crystal silicon substrate, the single-crystal silicon substrate is selectively subjected to wet etching process to form discrete ink passages in the substrate. This wet etching process is generally carried out using an alkaline aqueous solution of high concentration, e.g., a 5 wt % to 40 wt % potassium hydroxide solution.
For the formation of the nozzle plate, a thin plate (e.g., a stainless plate) having ink discharge orifices formed at predetermined determined positions is bonded onto the head base.
In the ink jet print head thus structured, in forming the head base by wet etching process, if the etching solution comes in contact with the PZT elements, the elements are frequently stripped off or damaged. Specifically, if the single-crystal silicon substrate is etched by use of, for example, an alkaline aqueous solution for an etching solution and the etching progresses to reach the vibrating plate, the alkaline solution or the etching reaction products pass through the vibrating plate to possibly damage the PZT elements, at the termination of the etching.
Meanwhile, the nozzle plate forming method in which a thin plate (e.g., a stainless plate) having ink discharge orifices formed at predetermined determined positions is bonded on the head base, requires complicated manufacturing process. Therefore, this method is not suitable for the mass production of ink jet print heads.